Actually, one of the biggest problems with the modern practice of medicine as I see it, is that MDs regardless of training, don't really fixate on either diagnosis or treatment - they fixate on how to please the patient in front of them.

And by "please" I mean they want to satisfy the patient well enough to avoid any unpleasantness, and do it quickly enough that they can see the next patient.

Telling the patient that you don't think he needs antibiotics for that viral infection accomplishes neither of these things. Most patients are going to be pissed off, and no doctor likes pissing off his patients.

It is also a truism among doctors that explaining to a patient why he doesn't need antibiotics takes much longer than just writing the prescription for antibiotics in the first place.

Intellectually, most people know that doctors over-prescribe lots of medications including antibiotics, but I can tell you from years of experience that it's a rare patient that shows up in the doctor's office with a viral infection who isn't a lot happier to leave with a prescription for pills that will help "clear it up".